Fiscal horsepower: how it is worked out and the tax you pay
Enter the engine size and number of cylinders, or an electric car’s power: you get the fiscal horsepower to two decimals and the road-tax band.
2026 road tax in Madrid
€59 / year
11.64 fiscal hp · 8 to 11.99 fiscal hp
| Band amount | €59 |
|---|---|
| Annual amount | €59 |
| Legal minimum and maximum (s. 95) | €34.08 – €68.16 |
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How the answer was reached, step by step
- Fiscal hp: 0.08 × (1,598 cc ÷ 4 cylinders)^0.6 × 4 = 11.64 (annex V RGV, four-stroke engine).
- Car band 8 to 11.99 fiscal hp: €59 in Madrid's 2026 tax byelaw (national minimum €34.08).
Estimate based on the byelaws and DGT criteria checked on 15 October 2026. The byelaw in force and, for the label, the DGT number-plate lookup have the final word. How we calculate
Fiscal horsepower (caballos fiscales, CVF) is calculated under annex V of the General Vehicle Regulation, Royal Decree 2822/1998. For a four-stroke combustion engine, CVF = 0.08 × (0.785 × D² × R)^0.6 × N, where D is the cylinder bore in centimetres, R the piston stroke and N the number of cylinders; since 0.785 × D² × R is the volume of one cylinder, the formula equals 0.08 × (engine size ÷ cylinders)^0.6 × cylinders. For a two-stroke engine the factor is 0.11. For electric and rotary engines, the effective power in kilowatts is divided by 5.152. The result is given to two decimals rounded down; it is the figure in box P.2.1 of the technical card and the one road tax uses to set the band.
Checked by Radif Partners · Editorial policy · How we calculate
Examples with the official formula
| Engine | Fiscal hp | Road-tax band |
|---|---|---|
| 999 cc, 3 cylinders | 7.82 | under 8 |
| 1,197 cc, 3 cylinders | 8.72 | 8 to 11.99 |
| 1,499 cc, 4 cylinders | 11.20 | 8 to 11.99 |
| 1,598 cc, 4 cylinders | 11.64 | 8 to 11.99 |
| 1,968 cc, 4 cylinders | 13.19 | 12 to 15.99 |
| 2,993 cc, 6 cylinders | 19.95 | 16 to 19.99 |
Note the jump between the 999 cc three-cylinder, under 8 hp, and the 1,197 cc one, already in the 8 to 11.99 band. A small three-cylinder engine saves the most tax, and moving up a band can double the bill.